816881791 has 8 divisors (see below), whose sum is σ = 894844368. Its totient is φ = 739536000.

The previous prime is 816881743. The next prime is 816881803. The reversal of 816881791 is 197188618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 816881791 - 2¹³ = 816873599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816881711) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151420 + ... + 156721.

It is an arithmetic number, because the mean of its divisors is an integer number (111855546).

Almost surely, 2^816881791 is an apocalyptic number.

816881791 is a deficient number, since it is larger than the sum of its proper divisors (77962577).

816881791 is a wasteful number, since it uses less digits than its factorization.

816881791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308393.

The product of its digits is 193536, while the sum is 49.

The square root of 816881791 is about 28581.1439764051. The cubic root of 816881791 is about 934.8022272271.

The spelling of 816881791 in words is "eight hundred sixteen million, eight hundred eighty-one thousand, seven hundred ninety-one".